During data transmission, communication devices (such as mobile phones) may emit radio frequency (RF) waves, a form of electromagnetic radiation. There are generally two types of electromagnetic radiation, ionizing and non-ionizing radiation. It is known that large doses of ionizing radiation (for example, X-rays, ultraviolet (UV) rays, and gamma rays) may cause cancer. There is concern that non-ionizing radiation (for example, visible light, microwaves and RF waves) may also cause cancer. Recent studies have indicated that there may be a link between the non-ionizing radiation (such as the radiation emitted from mobile phones) and cancer.